Field of Invention
This invention relates to a point of sale printer having a large paper roll supply, and, more particularly, to such a printer having a large supply paper roll mounted beneath a counter surface extending under the printer, and to apparatus for controlling the rotational acceleration and deceleration of a massive paper supply roll as movement of a paper web through the printer is suddenly started and stopped.
Point of sale printers have typically been used to print sales receipts. A recent trend in the use of such printers is an increased acceptance of thermal printing methods, which provide for operation at much faster printing speeds. The availability of faster printing speeds has led to including additional printed material on sales receipts. For example, many sales receipts now include store logos, advertisements, barcodes, and statements of store policy, especially regarding the return of purchased merchandise. Such additional printed material greatly increases the. length of typical receipts. While faster printing speeds allow the generation of such longer receipts without significantly slowing the checkout process, the increased length of receipts results in an increased frequency in which paper supply rolls must be changed.
A number of improvements have been made in the simplification of the process of loading new paper supply rolls, providing, for example, a xe2x80x9cdrop and loadxe2x80x9d feature for a point of sale terminal. An example of such an improvement is found in U.S. Pat. No. 5,060,877, which describes an automatic paperfeed apparatus including a receptacle for a paper roll. Within the receptacle, the paper roll rests upon a guide roll and a first feed roll which is capable of rotating the paper roll to feed a paper web from the roll. A guide chute is provided which guides movement of the paper web from the paper roll to an exit portion of the guide chute, from where it may be introduced into a printer or other device. The guide chute is comprised of a portion of the floor of the receptacle and a movable upper element. The movable upper element is pivotally mounted at one end on the shaft associated with the first feed roll. A second feed roll is positioned between the ends of the guide chute to drive the paper web through the guide chute, and cooperates with pressure rolls mounted on the upper element of the guide chute. A motor is provided for driving the first and second feed rolls.
While the time required to change paper supply rolls is certainly reduced by such improvements, a new paper supply roll must be found when it is needed, and the resulting process of changing rolls disrupts the process of checking out merchandise. Thus, what is needed is a way to provide significantly more paper in a single supply roll, so that the frequency of changing rolls is significantly reduced.
U.S. Pat. No. 4,808,800 describes apparatus for providing an additional and somewhat larger paper roll for an electronic printer calculator, which then contains rolls of paper outside and inside the calculator and a printer for printing out data on either of the rolls of paper. A passage for leading the roll paper set outside the calculator main body to the printer is separate from that for leading the roll paper set inside the calculator main body to the printer.
While the apparatus of U.S. Pat. No. 4,808,800 does provide for a somewhat larger roll of supply paper, what is needed is a much larger roll which is mounted in a location spaced away from the printing mechanism. Furthermore, what is needed is a method for dealing with the rotational inertia of a large roll of paper, both in terms of accelerating the roll to a peripheral speed sufficient to supply paper for a modem high-speed point of sale printer, and in terms of decelerating the roll when the printing process has been stopped without spooling off a substantial portion of the paper web.
Thus, it is a first objective of the present invention to provide a substantially larger paper supply roll for a point of sale terminal;
It is a second objective thereof to provide a means for rotationally accelerating a massive paper roll as a printer suddenly begins moving a paper web from the roll to print;
It is a third objective thereof to provide a means for minimizing the unspooling of a paper web during deceleration of a massive paper roll after a printer suddenly stops moving a paper web from the roll to print;
It is a fourth objective thereof to provide a means facilitating the loading of a massive paper roll into paper feed apparatus for a printer; and
It is a fifth objective thereof to provide a means for retaining a paper web extending upward into a printer in position within a paper feed apparatus when an upper end of the paper web is released by a printer.
It is a sixth objective thereof to provide a means to facilitate threading a paper web from a paper supply roll under the counter into a printer on the counter.
According to a first aspect of the. present invention, paper supply apparatus is provided for a printer having a paper drive moving a paper web through the printer in a paper feeding direction. The paper supply apparatus includes a roll mounting bracket, a spindle, a tensioning roller, and a tensioning roller support structure. The roll mounting bracket is disposed externally from the printer. The spindle removably and rotatably mounts a paper supply roll in the roll mounting bracket. The tensioning roller applies a tensioning force to a portion of the paper web extending between the paper supply roll mounted on the spindle and the printer. The tensioning rollersupport structure constrains the tensioning roller to move along a preferred path, with the tensioning roller moving along the preferred path in a first direction as the paper roll is accelerated to rotate in an unspooling direction in response to the paper drive starting to move the paper web through the printer, and with the tensioning roller moving along the preferred path opposite the first direction as the paper roll is decelerated in response to the paper drive stopping movement of the paper web through the printer.
According to a second aspect of the present invention, paper supply roll mounting apparatus is provided for a printer having a paper drive moving a paper web from a paper supply roll through the printer in a paper feeding direction. The paper supply apparatus includes a roll mounting bracket, a spindle, and a cable extending on each side of the spindle. The roll mounting bracket is disposed externally from the printer. The spindle removably and rotatably mounts a paper supply roll in the roll mounting bracket and includes a shaft having a first pulley attached at a first end of the shaft and a second pulley removably attached at a second end of the shaft. The cable engages the first and second pulleys between an anchor point and a handle, with the spindle being movable into the slot at each side of the roll mounting bracket while the spindle is held in suspension by the cable.